title: Absolute lymphocyte count: a cost-effective method of monitoring HIV-infected individuals.
abstract: OBJECTIVE
  Depletion of CD4 cell count is a hallmark of disease progression in AIDS. CD4 cell count is essential for physicians to decide about the timing of initiation of antiretroviral therapy (ART) and for prophylaxis of opportunistic infections. WHO has recommended that, absolute lymphocyte count (ALC) of ≤1200/μL can substitute CD4 cell count of ≤200/μL in resource-constrained countries throughout the world.
  
  
  METHODS
  This study was undertaken to know whether there is a correlation between CD4 cell count and ALC in HIV-infected individuals. A single sample of blood was withdrawn for ALC and CD4 cell count. The samples received from December 1, 2004 to December 31, 2005 were analyzed.
  
  
  RESULTS
  A total of 196 samples were collected from 185 patients. After exclusion, a total of 182 samples were analyzed. Results revealed that male:female ratio was 126:56 and their age ranged from 13 to 67 years. The median ALC was 1747 cells/μL, whereas the CD4 cell count ranged from 5 to 2848. The correlation coefficient between ALC and CD4 cell count was significant (0.714). There were 49 patients with an ALC of ≤1200/μL of whom 77.6% patients had CD4 cell count ≤ 200/μL (true positive) and 22.4% had CD4 cell count > 200/μL (false positive). There were 133 patients with an ALC of >1200/μL of whom 84.2% had CD4 cell count > 200/μL (true negative) and 15.8% had CD4 cell count ≤ 200/μL (false negative). Taking ALC of ≤1200/μL as a predictor of CD4 cell count ≤ 200/μL ,the sensitivity of the test was 64.4% and specificity was 91.1%. The positive predictive value was 77.6%, negative predictive value was 84.2%, and accuracy was 82.4%.
  
  
  CONCLUSIONS
  We found that an ALC of ≤ 1520/μL has higher sensitivity (78%) for a CD4 cell count of ≤ 200/μL. The ALC was found to be significantly cost-effective in our setup but chances of missing out patients requiring ART was 1 in 5 using the WHO guidelines.
authors.affiliation: Department of Medicine, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110 060, India.
authors.forename: A
authors.initials: A
authors.lastname: Kakar
authors.forename: R
authors.initials: R
authors.lastname: Beri
authors.forename: A
authors.initials: A
authors.lastname: Gogia
authors.forename: S P
authors.initials: SP
authors.lastname: Byotra
authors.forename: V
authors.initials: V
authors.lastname: Prakash
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: M
authors.initials: M
authors.lastname: Bhargava
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003362:Cost-Benefit Analysis; D005260:Female; D015658:HIV Infections / Q000175:diagnosis* / Q000276:immunology*; D006801:Humans; D018655:Lymphocyte Count / Q000191:economics; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D055815:Young Adult